PS Magazine - TB 43-PS-712
PS, The Preventative Maintenance Monthly
ISSUE 712
MARCH 2012
4
PS 712
MAR 12
END
Take a look at the humidity indicator card. If it is not blue, change out the desiccant
and check the card.
Sitting outside for 60 days, exposed to the elements, is a long time. During
extended storage, the humidity indicator should be checked at least every 30 days.
What about the Desiccant?
If the LLRC is equipped with a desiccant port, the desiccant should be placed in
the basket located inside of the port, never on the asset.
Consult the special packaging instructions for details on how much desiccant to
use. If you’re unable to determine how much is needed, contact LOGSA PSCC for
assistance at:
logsapscc.sr.tyad@us.army.mil
Increase Inspections
Increased inspection of containers awaiting shipment is important because most
metals suffer little or no corrosion while desiccant keeps the relative humidity below
50 percent. Once the humidity indicator starts to change color, it is time to replace
the desiccant within the desiccant port. If the humidity indicator goes back to blue,
the engine inside should be OK. But, the LLRC will need to be further monitored.
If the humidity indicator does not go back to blue, it may be necessary to open up
the LLRC to inspect the engine, check for other problems, and to replace the gasket
and desiccant.
Small Things Matter
The proper method of preservation per MIL-
STD 2073-1,
Standard Practice for Military
Packaging,
was followed and even the correct
LLRC was available. The LLRC still had its
original gasket and most of its bolts. Although
there were a few dings and dents around the
Fanges, it seemed OK to use.
Just before the top was about to be put on,
you tossed in some desiccant. One landed
on the engine, but so what, you thought. The
humidity indicator was blue, so it did not need
to be replaced, then.
Unfortunately,
so
many
engines
were
shipping back out, your LLRC sat in the yard
for more than 60 days without being checked.
The humidity indicator card started out blue,
but gradually changed to lavender and then
to pink, ±nally becoming all white. Is it any
wonder that the engine ended up in condition
code ²? What should have happened?
The same care used to ship an asset to the
joint operations area needs to be applied for
redeployments.
²irst, those dings and dents on the Fanges
might have prevented a good seal. They should
have been repaired. And the old gasket should
have been replaced. Think comparative cost: a
new gasket versus a new engine.
The top and bottom of the LLRC need to be
secured by
all of its bolts.
The four corner drill
may work well in basketball, but it didn’t seal
your LLRC!
Humidity indicator card:
A humidity indicator card has a moisture-
sensitive chemical that will change color
when the indicated relative humidity is
exceeded. It is an inexpensive way to
quantify relative humidity levels inside
sealed packaging. They are available in
many configurations and used in many
applications,
especially
military
and
semiconductor.
Desiccant:
A substance that induces or sustains
a state of dryness (desiccation) in its
local vicinity in a moderately well-
sealed container.
Pre-packaged
desiccant
is
most
commonly used to remove excessive
humidity that would normally degrade
or even destroy products sensitive to
moisture.
Remember that rusty
engine?
All
of its problems
could
have been prevented,
money and effort saved,
and readiness rates
improved…
…but
only
if all of
the necessary steps for
preventing
engine corrosion
had been followed.
What
should
have
happened?
Dings
and
dents on
flanges
fixed.
Old
gasket
replaced.
All
securing
bolts
should
have been
used.
When shipments are
delayed, desiccant can
become
saturated.
Check
containers
for increasing
humidity. if it
rises above
50 percent
humidity, action
is needed.
712 04-05.indd
1-2
1/31/12
10:29 AM
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